Help? Is it possible for the Plantronics CS55H Wireless Unit to work with a Northern Telecom Phone? Q: I already purchased the Plantronics CS55H Wireless Unit and I can’t get it to work with my Northern Telecom Phone? A: It will work with a small adjustment. You will need the phone filter cord, part # 66291-01. First you need to disconnect the 2 TR-1 connectors from the bottom of the CS55H since … Continued